Otto I of Brunswick-Luneburg

Otto I "the Young" of Brunswick-Luneburg (1204-9 June 1252) was the first Duke of Brunswick-Luneburg from 1235 to 1252, preceding Albert I of Brunswick-Luneburg and John of Brunswick-Luneburg.

Biography
Otto was born in 1204, the only son of William of Winchester and Helena of Denmark; he was a grandson of Henry the Lion of the House of Welf and Henry II of England of the House of Plantagenet on his father's side, and a grandson of Valdemar I of Denmark through his mother. He inherited his father's estates in 1213, and he allied with Valdemar II of Denmark, but this treaty injured Brunswick; Otto was imprisoned after the 1227 Battle of Bornhoved against the County of Holstein. Otto decided to mediate between the Pope and Hohenstaufens in hopes of gaining more power, and Frederick II of Germany rewarded him with the Duchy of Brunswick-Luneburg in 1235. He died in 1252, and his sons succeeded him.